In order to be able to authenticate a mechanical or electro-mechanical watch, the watch may be provided with an identification mark, particularly during manufacture. This identification mark may take the form of a code applied, for example, to an external part of the watch case which is not directly visible when the watch is worn on the wrist, to avoid making said watch less attractive. This code may be, for example, a coded image, such as a two-dimensional bar code as defined in EP Patent Application No. 1 804 195 A1. This coded image, which is obtained by specific calculation algorithms, is based on the identifier of the watch, which is generally sold with a card bearing said watch identifier. This code may be decrypted by a decrypted operation using decryption keys supplied by the parent company. Thus, in order to authenticate said watch, a specific computing device has to be used, which is slow and complicated and consequently a drawback.
The mechanical or electro-mechanical watch may thus include a personalised RFID circuit chip inside the watch case or camouflaged on an external part of the watch case. The identification code is thus stored in said RFID circuit chip so as to allow a nearby read device to read said identification code by wireless communication. This mark improves the protection of the watch against counterfeiting by authenticating the origin of said watch. However, as previously, it is necessary to have specific external means to be able to read and recognise the watch identification data, which constitutes a drawback.
FR Patent Application No. 2 630 228 A1 may also be cited, which discloses a perpetual calendar watch. This watch is provided with hands for the time display. The watch also includes an electronic control circuit and a time-setting stem, which can be subject to several manipulations, each relating to a determined function. The electronic circuit in the watch case is capable of recognising a code, which corresponds to a determined series of manipulations performed with the time-setting stem. This permits the change into a perpetual calendar programming mode, and particular programming to be carried out. The electronic circuit can recognise whether the code for the change into a programming mode has been correctly entered. However, this electronic circuit cannot operate the watch so as to provide authentication information regarding said watch.
In FR Patent Application No. 2 488 704 A1, in addition to the time base components, the analogue or digital watch includes a means of selecting a code to be transmitted by indicating the selection on a display device. The watch further includes a means of transferring the code via an electro-optical part, which displays the code in binary form. The code transmitted by the electro-optical part can be picked up by an opto-electronic processing device. As previously indicated, an external processing device has to be used to read the code or authenticate said watch, which constitutes a drawback.